var a = Math.pow(2,53) - 1
console.log(a)

console.log(a+2)



console.log(a+4)

console.log((2**53))
//9007199254740992

console.log(2 << 6)

// console.log(5 >> 1)  5/2取整
// console.log(-1 <<< 1)
console.log(128 / 2**6)

console.log(2000 - Math.floor(2000 / 3) * 3)
// 5
